In the jaw-dropping season finale, after Faye is attacked by the Witch Hunters, Jake, Melissa and Adam set out to save her. Blackwell (recurring guest star JOE LANDO) tells Cassie and Diana that the only way to stop the Witch Hunters is to use their Balcoin blood to unleash the Crystal Skull. While Diana is reluctant, Cassie convinces her it's the only way to help their friend, but she'll need to tap into her dark magic to do it. Meanwhile, Dawn and Charles are faced with a new way to get their power back ... but at a very big cost.

It's Prom night in Chance Harbor and after Adam uncloaks a crystal hidden in the school, Blackwell (recurring guest star JOE LANDO) tells Cassie she can use her dark magic to find it. When Cassie follows this advice, it leads her to a dangerous discovery. Meanwhile, Faye invites Jake to Prom, despite the fact that he stood her up two years earlier. Adam, Diana, Cassie and Melissa finally make it to Prom, but when they lose the crystal to Eben (recurring guest star SAMMI ROTIBI) they end up in a life and death situation. Meanwhile, Dawn attempts to stop Blackwell, who casts a deadly spell on Charles.

When a crystal is magically stolen from the abandoned house, the Circle decides it was the traitor witch working with Eben (recurring guest star SAMMI ROTIBI) so Jake calls for a meeting with Isaac (recurring guest star JR BOURNE – The Exorcism of Emily Rose) to see if they can get him to change sides. Cassie's loose grasp on her dark magic threatens to destroy any possible alliance when their pursuit of the traitor leads them to the "Creepiest Place on Earth." Meanwhile, Faye and Jake work together to steal Dawn's crystal, Melissa and Adam pair up and uncover a new magic trick and a frustrated Diana reaches out to Charles for help.

To protect themselves from the witch hunters, Jake, Cassie and Faye seek out Jake's grandfather Royce (guest star JOHN de LANCIE – Breaking Bad) to find his family's crystal and are confronted with disturbing theories about the events of 16 years ago. Meanwhile, Diana tries to balance her pursuit of the Glaser crystal with Melissa and Adam with her romantic life with Grant (recurring guest star TIM PHILLIPPS), who demands to know what she's hiding. At the same time, Callum (recurring guest star MICHAEL GRAZIADEI) attempts to reinsert himself into Melissa's life. Charles and Jane plot their move against Blackwell (recurring guest star JOE
LANDO).